Make .npmignore compatible with .gitignore format
Make .npmignore compatible with .gitignore format

Prior to this commit `eslint-plugin-node`'s "no-unpublish-require" rule failed
for "/tests" directory contents. It happens due to the fact that `ignore`
package which is used by `eslint-node-plugin` fails to recognize `/tests/(!helpers)`
exclusion pattern since this format is not  ".gitignore"-compliant.

@see: https://github.com/mysticatea/eslint-plugin-node/pull/106

balinterdi/ember-cli,thoov/ember-cli,mike-north/ember-cli,kellyselden/ember-cli,kellyselden/ember-cli,jgwhite/ember-cli,elwayman02/ember-cli,sivakumar-kailasam/ember-cli,ember-cli/ember-cli,gfvcastro/ember-cli,buschtoens/ember-cli,jgwhite/ember-cli,patocallaghan/ember-cli,ember-cli/ember-cli,twokul/ember-cli,gfvcastro/ember-cli,jgwhite/ember-cli,fpauser/ember-cli,ember-cli/ember-cli,ef4/ember-cli,sivakumar-kailasam/ember-cli,Turbo87/ember-cli,mike-north/ember-cli,kellyselden/ember-cli,HeroicEric/ember-cli,patocallaghan/ember-cli,patocallaghan/ember-cli,cibernox/ember-cli,fpauser/ember-cli,mike-north/ember-cli,thoov/ember-cli,HeroicEric/ember-cli,raycohen/ember-cli,raycohen/ember-cli,cibernox/ember-cli,buschtoens/ember-cli,jrjohnson/ember-cli,asakusuma/ember-cli,HeroicEric/ember-cli,Turbo87/ember-cli,HeroicEric/ember-cli,ef4/ember-cli,gfvcastro/ember-cli,twokul/ember-cli,fpauser/ember-cli,Turbo87/ember-cli,ef4/ember-cli,cibernox/ember-cli,twokul/ember-cli,sivakumar-kailasam/ember-cli,ef4/ember-cli,asakusuma/ember-cli,jgwhite/ember-cli,sivakumar-kailasam/ember-cli,kellyselden/ember-cli,gfvcastro/ember-cli,thoov/ember-cli,kategengler/ember-cli,Turbo87/ember-cli,elwayman02/ember-cli,twokul/ember-cli,thoov/ember-cli,kategengler/ember-cli,jrjohnson/ember-cli,balinterdi/ember-cli,patocallaghan/ember-cli,cibernox/ember-cli,fpauser/ember-cli,mike-north/ember-cli